1. Field of the Invention
The invention relates to a lens barrel which is used in an optical apparatus such as a photographing apparatus, an observing apparatus, or the like and to an optical apparatus having the lens barrel.
2. Related Background Art
A lens barrel is assembled into optical apparatuses such as photographing apparatuses like a video camera, a digital still camera, and the like for fetching a motion image or a still image by using a solid state image pickup device such as a CCD or the like arranged on a focusing surface of an optical system, observing apparatuses like a binocular, an astronomical telescope, and the like for observing an image of an object obtained by the optical system with the naked eyes, and the like.
Hitherto, various eccentricity adjusting mechanisms and adjusting methods for a single lens or lens unit have been proposed for the purpose of realizing further miniaturization and higher performance for a lens barrel having a size or optical performance that can be accomplished on the basis of the shape precision in a single part of a lens or a mechanical part or on the basis of a combination precision of each part.
For example, in the lens barrel proposed in the Official Gazette of Japanese Utility Model Registration Laid-Open No. 5-36410, a proper rattle is provided between the outer peripheral surface of the lens and the inner peripheral surface of a lens holding member for holding it, and a plurality of adjusting screws are screwed into the lens holding member from the outer peripheral direction to thereby make the lens holding member come into contact with the lens, thereby making an eccentricity adjustment.
In JP-A-6-265766, the method whereby laser beams are caused to be passed through two lens systems and the resultant image formation is image-processed, so that an eccentricity adjustment is made by an adjusting tool, and a lens is adhered and fixed at an adjusted position has been proposed.
However, in the above conventional examples, the lens barrel proposed in the Official Gazette of Japanese Utility Model Registration Laid-Open No. 5-36410 has a problem such that since the eccentricity adjusting mechanism is assembled in the lens barrel, the size of the lens barrel increases in the radial direction. When the lens holding member is made of plastics, since it is necessary to design a hook of the screw so that it is longer than the lens holding member made of metal, the lens barrel becomes larger.
Moreover, since the lens is directly supported at a plurality of points, there are also problems such that the lens surface is deformed by the adjustment and, in the case of a heavy lens, the lens is broken by an impact load which is applied to the lens, or an adjusting position is shifted.
On the other hand, according to the method proposed in JP-A-6-265766, since the eccentricity adjustment is made by an adjusting tool which is externally attached, it is advantageous in terms of the size of the lens barrel. However, since the eccentricity adjusted lens is fixed only with the adhesive agent in both of the optical axial direction and the eccentricity adjusting direction, there is a problem such that softening or embrittlement of the adhesive agent, peel-off of the adhesive surface, or the like occurs in the case where an impact load is applied, due to a thermal and moist environment, or due to an external factor such as an abrupt temperature change or the like, so that the lens position is shifted.
It is an object of the invention to provide a lens barrel having an eccentricity adjusting mechanism having high positional reliability in a small space.
To accomplish the above object, according to the invention, there is provided a lens barrel comprising:
a lens holding barrel which holds a lens and has a first flange portion for preventing movement of the lens in the direction of an optical axis and permitting movement of the lens in a direction perpendicular to the optical axis and a ring-shaped guide surface;
an intermediate ring which is movably provided on the guide surface of the lens holding barrel and has a wedge portion; and
a supporting barrel which supports the lens holding barrel and has a second flange portion adapted to be come into engagement with the first flange portion of the lens holding barrel and a wedge receiving portion which comes into contact with the wedge portion of the intermediate ring, in which the lens holding barrel is moved in a direction perpendicular to the optical axis for eccentricity adjustment, in a state where the lens holding barrel is moved, the intermediate ring is moved on the guide surface of the lens holding barrel, and the wedge portion comes into contact with the wedge receiving portion in this state, thereby fixing the lens holding barrel and the intermediate ring to the supporting barrel.
According to the invention, there is provided a lens barrel comprising:
a lens holding barrel which holds a lens and has a first flange portion for preventing movement of the lens in the direction of an optical axis and permitting movement of the lens in a direction perpendicular to the optical axis and a ring-shaped guide surface;
an intermediate ring which is movably provided on the guide surface of the lens holding barrel and has a wedge portion;
a supporting barrel which supports the lens holding barrel and has a second flange portion adapted to be come into engagement with the first flange portion of the lens holding barrel and a wedge receiving portion which comes into contact with the wedge portion of the intermediate ring, in which the lens holding barrel is moved in the direction perpendicular to the optical axis for eccentricity adjustment, in a state where the lens holding barrel is moved, the intermediate ring is moved on the guide surface of the lens holding barrel, and the wedge portion comes into contact with the wedge receiving portion in this state, thereby fixing the lens holding barrel and the intermediate ring to the supporting barrel; and
fixing means for fixing the lens holding barrel, the intermediate ring, and the supporting barrel.
According to the invention, there is further provided a lens barrel comprising:
a lens holding barrel which holds a lens of a cylindrical shape, holds a lens and has at least three first flange portions for preventing movement of the lens in the direction of an optical axis and permitting movement of the lens in a direction perpendicular to the optical axis and a ring-shaped guide surface having a spherical surface;
an intermediate ring which is movably provided along the spherical surface of the guide surface of the lens holding barrel so that it can be freely inclined in the optical axial direction and to the optical axis, in which the intermediate ring has, on its inner peripheral surface, a cylindrical portion such that a straight line is set to the optical axis direction and which comes into contact with the spherical surface of the guide surface of the lens holding barrel and has at least three wedge portions on its outer peripheral surface;
a cylindrical supporting barrel which supports the lens holding barrel and has at least three second flange portions adapted to come into engagement with the first flange portions of the lens holding barrel and at least three wedge receiving portions which come into contact with the wedge portions of the intermediate ring, in which the lens holding barrel is moved in a direction perpendicular to the optical axis for eccentricity adjustment, in a state where the lens holding barrel is moved, the intermediate ring is moved on the guide surface of the lens holding barrel, and the wedge portions come into contact with the wedge receiving portions in this state, thereby fixing the lens holding barrel and the intermediate ring to the supporting barrel; and
an adhesive portion at which contact portions of the lens holding barrel, the intermediate ring, and the supporting barrel are adhered with an adhesive agent.
The above and other objects and features of the present invention will become apparent from the following detailed description and the appended claims with reference to the accompanying drawings.